How to Use Heat Shrink Tubing

Co-authored by Marvin Woo and Hunter Rising

Last Updated: December 6, 2021 References

Heat shrink tubing, also known as a shrink sleeve, can be used to repair and insulate wires and cables. After you slide the tubing onto the cable you’re fixing, use a heat gun or other heat source to make it shrink and create a tight seal. You can also use heat shrink tubing around your home to repair other items, such as frayed shoelaces or broken glasses. With the right tubing and a little bit of practice, you’ll be able to make repairs quick and easy!

Method 1

Method 1 of 2:

Insulating Wires with Heat Shrink Tubing

1
Measure the wire with a wire gauge tool. Feed the wire that you plan on applying heat shrink wrap to into one of the holes on a wire gauge tool to see if it’s a tight fit. If the wire can move around inside the hole on the tool, then try checking the next size down. Once you can feed the wire into a hole and it doesn’t shift around while it’s inserted, then write down the size of the gauge so you know what tubing to buy.^{[1]
X
Research source}
- You can buy a wire gauge tool from your local hardware store.
- You don’t need to strip the insulation off of the wire if it already has it since the heat shrink tubing will go around it.
- If the wire doesn’t fit in the wire gauge tool or has an irregular shape, then you can also use a ruler or tape measure to find the diameter.
2
Pick tubing that has a shrunken diameter smaller than the wire you’re insulating. Look on the packaging to find the diameter of the tube before shrinking it as well as the shrink ratio it has, which is usually between 2:1 and 6:1. Divide the diameter of the shrink tubing by the first number in the ratio to find its shrunken diameter. Calculate which tubing will shrink to a size smaller than the diameter of your wire to ensure that it has a tight seal.
- For example, if the original diameter of the tubing is ¹⁄₂ inch (1.3 cm) and it has a 2:1 shrink ratio, then it will become ¹⁄₄ inch (0.64 cm) once you heat it. If it had a 3:1 ratio, then it would be ¹⁄₆ inch (0.42 cm) after you shrink it.
- You can buy heat shrink tubing from hardware stores or online.
- Get heat shrink tubing that matches the color of your wire if you want it to blend in more.
Tip: Make sure the tubing has a large enough diameter so you can slide it over any wires or connections to guide it into place.

Advertisement
3
Cut the tubing ¹⁄₂ in (1.3 cm) longer than the section you’re covering. Measure the length of the wire section that you need to cover with the tubing and then add an additional ¹⁄₂ inch (1.3 cm). The extra length of tubing will cover the insulation on the wire around the area you’re covering to ensure that it makes a tight seal and doesn’t leave any wire exposed. Use a pair of scissors to cut the tubing to size.
- The heat shrink tubing may also shrink lengthwise by about 5-7% when you heat it, so you can add more to the length if you want to.
4
Slide the tubing onto the cable to cover the section you need to insulate. Once you cut the tubing to size, feed the end of the wire through the middle of the tubing. Continue sliding the tubing down the length of wire until you reach the area you’re insulating.^{[2]
X
Expert Source

Marvin Woo
Licensed Electrician
Expert Interview. 1 December 2021.} Make sure the tube’s positioned so it extends ¹⁄₄ inch (0.64 cm) past the section on each side so the exposed wires are sealed.^{[3]
X
Research source}
- If you’re covering up a wire splice, position the tubing over the center of the splice so it overlaps both sides equally.
5
Heat the tubing with a heat gun so it shrinks around the wire. Hold a heat gun about 3–6 inches (7.6–15.2 cm) away from the tubing and turn it on. Move the nozzle of the heat gun back and forth along the length of tubing so it starts to shrink. Rotate the wire so you can heat all sides of the tubing evenly to make sure it shrinks to size and that there are no air bubbles inside. Continue heating the tubing until its tight against the wires underneath it.^{[4]
X
Research source}^{[5]
X
Expert Source

Marvin Woo
Licensed Electrician
Expert Interview. 1 December 2021.}
- You can also rub the tubing with the side of a soldering iron to shrink it, but be careful not to heat it too much since you could damage the wires underneath or make the tubing brittle.
- You may hold the tubing over the open flame of a lighter, but it won’t heat evenly and you may not have a perfect seal.
- Hair dryers may not be hot enough to make the tubing shrink, but you can try using one on the highest heat setting.
- The shrinking temperature for the tubing can usually be found on the packaging.
6
Let the tubing cool completely before you apply any stress to it. Leave the tubing for about 5 minutes so it has a chance to cool around the wire. Once it’s cool to the touch, you can handle and bend the wire into the position you need.

Method 2

Method 2 of 2:

Using Heat Shrink Tubing around the House

1
Reinforce a headphone jack so it doesn’t break or bend. Choose heat shrink tubing that has a shrunken diameter that’s slightly smaller than the diameter of your headphone jack. Slide the tubing over the headphone jack so it overlaps where the headphone cord comes out of the base. Heat the tubing over the headphone jack to shrink it in place and make a more rigid connection.^{[6]
X
Research source}
- Be careful not to melt any of the plastic on the actual headphone wire since you could cause damage to the wires or expose them.
- Applying heat shrink tubing to a headphone jack that’s already broken won’t fix it.
2
Prevent shoelaces from fraying by sealing the ends in shrink tubing. Aglets, the plastic ends on shoelaces, prevent your shoelaces from falling apart, but they may break off over time. Cut heat shrink tubing so it’s about 1 inch (2.5 cm) long and slide it onto the end of your shoelace. Use a heat gun to shrink the tubing so it holds the end of the laces tight so it doesn’t fray anymore. ^{[7]
X
Research source}
- Use shrink tubing that’s clear or the same color as your shoes so it doesn’t clash.
3
Fix broken glasses frames with heat shrink tubing. If the arm broke off your glasses, slide 1–1 ¹⁄₂ inches (2.5–3.8 cm) of heat shrink tubing onto it. Use tubing that’s the same color as your frames so it blends in well. Hold the broken glasses arm against your frames and guide the tubing over the joint. Use your heat gun to shrink the tubing so the glasses arm stays in place.^{[8]
X
Research source}
- Be careful heating plastic glasses frames since you could distort their shape if it gets too warm.
4
Add heat shrink tubing to keys to identify them easier. Get multiple colors of heat shrink tubing that are large enough to fit over the largest ends of your keys. Slide the tubing over the key and use a heat gun or another heat source to shrink it. Once the tubing is tight around your key, use a small screwdriver to poke a hole through in the tubing so you can still put the key on a ring. Use a different color for each key so you can easily find the one you need quickly.^{[9]
X
Research source}
- Putting heat shrink tubing on your keys also prevents them from making a lot of noise when you pick them up or set them down.
5
Put heat shrink tubing on tool handles so you can get a better grip on them. If you have tools in your toolbox that don’t have a plastic grip, you can easily add one with heat shrink tubing. Get tubing that has a shrunken diameter that’s smaller than the diameter of the tool’s handle and cut it to size with a pair of scissors.^{[10]
X
Research source}
- Metal tools may get hot as you heat up the tubing, so wear work gloves while you’re applying the handle.
Tip: Label the heat shrink tubing with the size of the tool so you can see it easily from a distance. That way, you can avoid sifting through your tools to find the right size.

Expert Q&A

Question

Can you heat shrink wires?

Marvin Woo
Licensed Electrician
Marvin Woo is a licensed electrician and the Owner of Woo's Electrical & Appliance based in East O’ahu. With over two decades of experience, he specializes in troubleshooting issues and maintaining residential electrical systems. Marvin is both licensed and insured to complete electrical work in the state of Hawaii.

Marvin Woo

Licensed Electrician

Expert Answer

Definitely! Just make sure that the tubing is slightly larger than the diameter of the wiring so it can easily slip on and shrink tight enough when heated.

Warnings

Don’t heat the shrink tubing too long or else it could turn brittle or char.

⧼thumbs_response⧽
Helpful 0 Not Helpful 0
Make sure any wires are unplugged so you don’t get shocked or electrocuted.

⧼thumbs_response⧽
Helpful 0 Not Helpful 0